1. Field of the Invention
This invention relates to a dentifrice composition, and in particular, to one which contains an effective amount of cationic anti-decay agent plus a nonionic surfactant which provides adequate foaming properties without imparting an unpleasant taste.
2. Description of the Prior Art
Including an anti-decay agent in a dentifrice (tooth powder or paste) is known. See, for example, U.S. Pat. No. 3,989,813, where there is provided a dentifrice containing 1,6-di-(p-chlorophenyl biguanidohexane) as an agent which inhibits the growth of many microorganisms such as Lactobacillus acidophilus odontolyticus, and U.S. Pat. No. 3,984,537, which teaches use of a non-toxic amino-cyano polymeric diguanide or salt thereof. The latter patent teaches that its polymeric diguanides are cationic but compatible with anionic substances and other materials usually present in oral preparations. The disclosures of the above-mentioned patents notwithstanding, it has not been usual to include in a dentifrice, especially in a toothpaste, an anti-decay agent of cationic nature, largely because it has been usual to employ as a part of the composition a high-foaming surfactant, and to be more specific, usually a high-foaming surfactant of anionic nature. In general, the use of an anionic surfactant for foam generation is not compatible with the use of a cationic agent for control of decay (caries); the two, if used together, will with rare exceptions react and cancel each other.
Including a dentifrice a nonionic surfactant with unobjectionable taste and considerable foaming properties is also not new. See, for example, the formulation designated "No. 9" on page 330 of A Formulary of Cosmetic Preparations, compiled by Michael and Irene Ash (Chemical Publishing Co., New York, 1977), in which 2 percent of "Pluronic F-87" surfactant is used in the making of a toothpaste. That particular formulation or recipe does not contain any cationic anti-decay agent. "Pluronic F-87" polyol is nonionic, a block copolymer with an internal block of PO units contributing an average molecular weight of 2,250 and external blocks of EO units which, between them, contribute approximately 70 percent of the molecular weight of the total molecule. It is known to chemists who are familiar with surfactants as perhaps the highest-foaming member of the family of "Pluronic" polyols. It is also not inexpensive to manufacture because its manufacture necessarily involves not one but two separate polymerization operations which are conducted at superatmospheric pressure and moderately elevated temperature. Another point of difference between " Pluronic F-87" and the nonionic surfactants used according to the present invention is that the latter are substantially more highly biodegradable than the former.
Reference may be had to the above-mentioned work by Michael and Irene Ash for examples of formulations known to be useful for making toothpaste. A typical toothpaste contains
about 40 to 50 percent polishing agent, most usually dicalcium phosphate, possibly replaced in part by other mild abrasives such as chalk, clay, and other phosphates; PA0 about 0.5 to 3 percent of detergent, most usually either 1.5 or 2 percent of sodium lauryl sulfate; PA0 about 10 to 25 percent of sorbitol syrup (usually 70 percent active ingredient); PA0 about 10 to 30 percent of glycerin, with the proviso that if either the sorbitol or the glycerin is omitted, the other one of the two is used liberally; PA0 about 0.15 to 0.2 percent of sodium saccharin, although this is sometimes omitted or replaced with other sweetener; PA0 about 0.5 to 3 percent of flavoring oils, usually about 1 percent or less, peppermint oil being popular; PA0 about 1 to 2 percent of binding agent such as magnesium aluminum silicate (VEEGUM F), sodium carboxymethyl cellulose, methyl cellulose, Irish moss, etc., singly or in combination; PA0 about 0.2 to 1 percent of a preservative such as methylparaben, propylparaben, or sodium benzoate; PA0 and the remainder mostly water plus, in some cases, small amounts of other ingredients such as therapeutic agent, dye, etc. PA0 40 to 50 percent of polishing agent; PA0 0 to 21 percent of sorbitol; PA0 0 to 30 percent of glycerol, with the proviso that the sum of the glycerol and sorbitol is 20 to 40 percent; PA0 1 to 2 percent of binding agent; PA0 0.2 to 1 percent of preservative; PA0 0.5 to 3 percent of flavoring agent; PA0 0 to 0.5 percent of sweetening agent; PA0 an effective amount of an anti-decay agent of cationic nature; PA0 0.5 to 3 weight percent of a foaming nonionic surfactant which is an adduct of the formula EQU R--(OA).sub.n --H PA0 where R is an alkyl radical containing 15 to 16 carbon atoms; PA0 A is a bivalent alkylene radical containing 2 to 4 carbon atoms, such that individual OA units may be the same or different, and the number of OA units in which A contains 3 or 4 carbon atoms is such as to account for from 0 to 10 percent of the molecular weight of the adduct, and the positioning of OA units in which A contains 3 or 4 carbon atoms in the molecule is such that they are present either as a block proximate to the radical R or randomly distributed through the length of the chain indicated by portion --(OA).sub.n -- of the above formula; PA0 n is a number such that said portion --(OA).sub.n -- accounts for 50 to 75 percent of the molecular weight of said adducts; and PA0 the remainder substantially water. PA0 N.sup.1 -(4-chlorobenzyl)-N.sup.5 -(2,4-dichlorobenzyl) biguanide; PA0 p-chlorophenyl biguanide; PA0 4-chlorobenzhydryl biguanide; PA0 4-chlorobenzhydrylguanylurea; PA0 N.sup.3 -lauroxypropyl-N.sup.5 -p-chlorobenzylbiguanide; PA0 1,6-di-(p-chlorophenylbiguanidohexane); PA0 1-(lauryldimethylammonium)-8-(p-chlorobenzyldimethylammonium)-octane dichloride; PA0 5,6-dichloro-2-guanidinobenzimidazole; PA0 N.sup.1 -p-chlorophenyl-N.sup.5 -laurylbiguanide; PA0 5-amino-1,3-bis(2-ethylhexyl)-5-methylhexahydropyramidine; and their non-toxic acid addition salts, particularly those where the anion includes a fluorine atom, such as: fluoride, monofluorophosphate, hexafluorosilicate and hexafluoroaluminate.
In the field of nonionic surfactants made by oxyethylating fatty alcohols, fatty acids, fatty amides, fatty amines, or alkylphenols, the effects upon foaming properties of adding various numbers of oxyethylene units have been investigated--see page 336 of Surface Active Ethylene Oxide Adducts by Schoenfeldt (Pergamon Press, London, 1969). It reports the work of K. Tagawa et al. published in Kogyo Kagaku Zasshi, 65, 949-953 (1962), from which we know that various EO adducts of cetyl alcohol (C.sub.16 H.sub.33 OH) have been made and tested for foaming performance. The prior art does not, to my knowledge, contain any indication of the taste characteristics of these or other EO adducts of fatty alcohols.